The present invention is directed to a low-profile culvert structure composed essentially of interconnecting corrugated metallic sheets to form the shell, and corrugated metallic sheets secured to said shell for support.
One structural limitation of low profile culverts, i.e. low rise to span ratio, is the susceptibility to failure by deflection or flattening during installation, and more particularly during use. A recent attempt to develop a low-profile, corrugated culvert structure, resistant to a susceptibility to flatten, is described in U.S. Pat. No. 4,141,666 to DeGraff. The culvert described therein is characterized by a shell formed of interconnecting arch-shaped corrugated metal sheets. Support for the shell is provided by cross-ribs, in the form of aluminum extrusions, and by stringers, i.e. box-shaped aluminum extrusions, extending substantially the entire length of the culvert structure along the interior of the shell. The latter supports are a critical feature of the DeGraff structure. The stringers, by extending substantially the entire length of the structure, (1) act as stiffening members and strengthen the culvert against collapse, (2) act to integrate the various sections of the shell into a single unitary structure, and thereby distribute overhead loads throughout the structure, and (3) replace the support typically provided in prior art culvert structure by flooring.
The low-profile culvert structure of the present invention, while presenting a geometry profile similar to that of DeGraff, is readily distinguishable therefrom by the absence of such stringer supports extending substantially the entire length of the culvert structure. Further distinguishing features will be apparent by the description which follows.